Display panel or portion thereof with a transitional graphical user interface



FIG. 1 is a front view of a display panel or portion thereof with a transitional graphical user interface showing a first image in a sequence according to our new design; and,

FIG. 2 is a front view of a display panel or portion thereof showing a second image in the sequence according to our new design.

The appearance of the transitional graphical user interface sequentially transitions between the images shown in FIG. 1 to FIG. 2 and FIG. 2 to FIG. 1. The process or period in which one graphical user interface transitions into another forms no part of the claimed design.

The broken lines illustrate a display panel or portion thereof that form no part of the claimed design. The broken lines also illustrate portions of the graphical user interface that form no part of the claimed design. 

CLAIM The ornamental design for a display panel or portion thereof with a transitional graphical user interface, as shown and described. 